The best strategy for negotiating a deal

Hi BP family, I have a quick question for all experienced investors (or anybody who's been in this situation).

I'm curious what's the best strategy you've found for negotiating a deal? Do you always aim for a win-win situation? Are there times in your experience when taking a loss would be advantageous in the long run, etc.

Reading a book and googling the "negotiating strategies" is one thing, but coming from a newbie investor, I'd love to hear your perspectives and stories. Is there a special tactic you've found that works for you, that hasn't already been mentioned online? Thanks again BP family :)